Apparatus and method for producing shaded images on display screens

• US 5,751,265 A
• Filed: 05/16/1995
• Issued: 05/12/1998
• Est. Priority Date: 12/24/1991
• Status: Expired due to Term

• Current Assignee: NVIDIA Corporation
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Han, Robin Sungsoo
• Primary Examiner(s): SARAS, STEVEN J
• Application Number:
  US08/442,836
• Time in Patent Office: 1,092 Days
• Field of Search: 345/88, 345/89, 345/113, 345/136, 345/139, 345/147-150, 345/152, 345/153, 382/169, 358/429, 358/455
• US Class Current: 345/88
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• CPC Class Codes: G09G 3/2077 by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A process for producing a wide range of shades in images that are presented in successive frames on image fields on opto-electronic display means having at least one illumination element at each of a plurality of pixel locations. Each pixel location, for example, may have a red, a green and a blue illumination element. The display is divided into uniformly-sized display neighborhoods. The process includes, for a given pixel location within any one of the uniformly-sized display neighborhoods, producing a given shade at that pixel location by selecting a frame sequence for illuminating the illumination elements at the pixel location during presentation of an image wherein the number of times that any given illumination element at the pixel location is illuminated within a given frame sequence is controlled to create an appearance of shading of that pixel location relative to other pixel locations and wherein adjacent pixel locations that have the same shade within any one of the display neighborhoods have their illumination elements illuminated with different frame sequences to minimize display noise.

Claims

1. A method of displaying, over a number of consecutive frames, an image with a shade on a display device that includes an array of pixels, each pixel including an illumination element, the method comprising:

providing a display pattern representing the image in an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels; and

illuminating the illumination element of the pixels of the image in response to the display pattern in accordance with a predetermined illumination sequence, such that

i) only one pixel of the image per frame, in the display neighborhood, has its illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are at least one pixel apart.

2. The method as in claim 1, wherein the predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

3. A method of displaying, over a number of consecutive frames, an image with one or more shades on a display device that includes an array of pixels, each pixel including an illumination element, the method comprising:

providing a display pattern representing the image in an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels;

identifying a first predetermined illumination sequence, the first predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has its illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose illumination is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are at least one pixel apart; and

illuminating the illumination element of the pixels of the image in accordance with a second predetermined illumination sequence, the second predetermined illumination sequence being such that

i) the illumination element of only K pixels of the image in the display neighborhood are illuminated in a frame (where K<

N×

M and not equal to (N×

M)/2), and

ii) the K pixels whose illumination element is illuminated in the frame correspond to pixels whose illumination element would be illuminated over K consecutive frames of the first predetermined illumination sequence.

4. The method of claim 3, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

5. The method of claim 3, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose illumination element is illuminated are substantially equal.

6. A display device that includes an array of pixels, each pixel including an illumination element, for displaying an image with a shade over a number of consecutive frames, the display device comprising:

means for providing a display pattern representing the image for an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels; and

means for illuminating the illumination element of the pixels of the image in response to the display pattern in accordance with a predetermined illumination sequence, such that

i) only one pixel of the image per frame, in the display neighborhood, has its illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are at least one pixel apart.

7. The display device of claim 6, wherein the predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the illumination element of the other pixels of the image, in the display neighborhood, is illuminated.

8. A display device that includes an array of pixels for displaying, over a number of consecutive frames, an image with one or more shades, comprising:

means for providing a display pattern representing the image for an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels;

means for identifying a first predetermined illumination sequence, the first predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has its illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose illumination element is illuminated in consecutive frames are at least one pixel apart; and

means for illuminating the illumination element of the pixels of the image in accordance with a second predetermined illumination sequence, the second predetermined illumination sequence being such that

i) the illumination element of only K pixels of the image, in the display neighborhood, are illuminated in a frame (where K<

N×

M and not equal to (N×

M)/2), and

ii) the K pixels whose illumination element is illuminated in the frame correspond to pixels whose illumination element would be illuminated over K consecutive frames of the first predetermined illumination sequence.

9. The display device of claim 8, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

10. The display device of claim 8, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose illumination element is illuminated are substantially equal.

11. A method of displaying, over a number of consecutive frames, an image with a color shade on a display device that includes an array of pixels, each pixel including a plurality of illumination elements, each of a different color, the method comprising:

providing a display pattern representing the image in an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels; and

illuminating a particular color illumination element of the pixels of the image in response to the display pattern in accordance with a predetermined illumination sequence, such that

i) only one pixel of the image per frame, in the display neighborhood, has its particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are at least one pixel apart.

12. The method as in claim 11, wherein the predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

13. A method of displaying, over a number of consecutive frames, an image with one or more color shades on a display device that includes an array of pixels, each pixel including a plurality of illumination elements, the method comprising:

providing a display pattern representing the image in an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels;

identifying a first predetermined illumination sequence, the first predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has a particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose particular color illumination is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are at least one pixel apart; and

illuminating the particular color illumination element of the pixels of the image in accordance with a second predetermined illumination sequence, the second predetermined illumination sequence being such that

i) the particular color illumination element of only K pixels of the image in the display neighborhood are illuminated in a frame (where K<

N×

M and not equal to (N×

M)/2), and

ii) the K pixels whose particular color illumination element is illuminated in the frame correspond to pixels whose particular color illumination element would be illuminated over K consecutive frames of the first predetermined illumination sequence.

14. The method of claim 13, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

15. The method of claim 13, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose particular color illumination element is illuminated are substantially equal.

16. The method of claim 13, wherein said particular color is a first particular color, and a second particular color is different from said first particular color, and further comprising:

identifying a third predetermined illumination sequence, the third predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has its second particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose second particular color illumination is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose second particular color illumination element is illuminated in consecutive frames are at least one pixel apart; and

illuminating the second particular color illumination element of the pixels of the image in accordance with a fourth predetermined illumination sequence, the fourth predetermined illumination sequence being such that

i) the second particular color illumination element of only L pixels of the image in the display neighborhood are illuminated in a frame (where L<

N×

M and not equal to (N×

M)/2), and

ii) the L pixels whose second particular color illumination element is illuminated in the frame correspond to pixels whose second particular color illumination element would be illuminated over L consecutive frames of the third predetermined illumination sequence.

17. The method of claim 16, wherein K is equal to L.

18. The method of claim 16, wherein K is not equal to L.

19. The method of claim 16, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the first particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the first particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated, and

wherein the third predetermined illumination sequence is further such that

v) over the number of consecutive frames, the second particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the second particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

20. The method of claim 16, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose first particular color illumination element is illuminated are substantially equal, and

wherein the third predetermined illumination sequence is further such that

v) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose second particular color illumination element is illuminated are substantially equal.

21. A display device that includes an array of pixels, each pixel including a plurality of illumination elements, each of a different color, for displaying an image with a color shade over a number of consecutive frames, the display device comprising:

means for providing a display pattern representing the image for an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels; and

means for illuminating a particular color illumination element of the pixels of the image in response to the display pattern in accordance with a predetermined illumination sequence, such that

i) only one pixel of the image per frame, in the display neighborhood, has its particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are at least one pixel apart.

22. The display device of claim 21, wherein the predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the particular color illumination element of the other pixels of the image, in the display neighborhood, is illuminated.

23. A display device that includes an array of pixels for displaying, over a number of consecutive frames, an image with one or more shades of a color, comprising:

means for providing a display pattern representing the image for an N×

M pixel display neighborhood (where N,M≧

4) within the array of pixels;

means for identifying a first predetermined illumination sequence, the first predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has a particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose particular color illumination element is illuminated in consecutive frames are at least one pixel apart; and

means for illuminating the particular color illumination element of the pixels of the image in accordance with a second predetermined illumination sequence, the second predetermined illumination sequence being such that

i) the particular color illumination element of only K pixels of the image, in the display neighborhood, are illuminated in a frame (where K<

N×

M and not equal to (N×

M)/2), and

ii) the K pixels whose particular color illumination element is illuminated in the frame correspond to pixels whose particular color illumination element would be illuminated over K consecutive frames of the first predetermined illumination sequence.

24. The display device of claim 23, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

25. The display device of claim 23, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose particular color illumination element is illuminated are substantially equal.

26. The display device of claim 23, wherein said particular color is a first particular color, and a second particular color is different from said first particular color, and further comprising:

means for identifying a third predetermined illumination sequence, the third predetermined illumination sequence being such that

i) only one pixel of the image per frame, in the display neighborhood, has its second particular color illumination element illuminated,

ii) pixels of the image, in the display neighborhood, whose second particular color illumination is illuminated in consecutive frames are a substantially equal number of pixels apart, and

iii) the pixels of the image, in the display neighborhood, whose second particular color illumination element is illuminated in consecutive frames are at least one pixel apart; and

means for illuminating the second particular color illumination element of the pixels of the image in accordance with a fourth predetermined illumination sequence, the fourth predetermined illumination sequence being such that

i) the second particular color illumination element of only L pixels of the image in the display neighborhood are illuminated in a frame (where L<

N×

M and not equal to (N×

M)/2), and

ii) the L pixels whose second particular color illumination element is illuminated in the frame correspond to pixels whose second particular color illumination element would be illuminated over L consecutive frames of the third predetermined illumination sequence.

27. The display device of claim 26, wherein K is equal to L.

28. The display device of claim 26, wherein K is not equal to L.

29. The display device of claim 26, wherein the first predetermined illumination sequence is further such that

iv) over the number of consecutive frames, the first particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the first particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated, and

wherein the third predetermined illumination sequence is further such that

v) over the number of consecutive frames, the second particular color illumination element of each pixel of the image, in the display neighborhood, is illuminated in a substantially equal number of frames as the second particular color illumination element of each of the other pixels of the image, in the display neighborhood, is illuminated.

30. The display device of claim 26, wherein the first predetermined illumination sequence is further such that

iv) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose first particular color illumination element is illuminated are substantially equal, and

wherein the third predetermined illumination sequence is further such that

v) over the number of frames, the numbers of frames between which each particular pixel of the image, in the display neighborhood, whose second particular color illumination element is illuminated are substantially equal.